Dielectric soil water content measurements independent of soil properties

2003 ◽  
Author(s):  
T. Flaschke ◽  
H.-R. Trankler
Keyword(s):  
Soil Properties ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content

scholarly journals Using Multivariate Geostatistics to Assess Patterns of Spatial Dependence of Apparent Soil Electrical Conductivity and Selected Soil Properties

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Glécio Machado Siqueira ◽  
Jorge Dafonte Dafonte ◽  
Montserrat Valcárcel Armesto ◽  
Ênio Farias França e Silva
Keyword(s):  
Electrical Conductivity ◽  
Soil Properties ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Clay Content ◽  
Data Sets ◽  
Soil Electrical Conductivity ◽  
Multivariate Geostatistics ◽  
Northwestern Spain

The apparent soil electrical conductivity (ECa) was continuously recorded in three successive dates using electromagnetic induction in horizontal (ECa-H) and vertical (ECa-V) dipole modes at a 6 ha plot located in Northwestern Spain. One of the ECadata sets was used to devise an optimized sampling scheme consisting of 40 points. Soil was sampled at the 0.0–0.3 m depth, in these 40 points, and analyzed for sand, silt, and clay content; gravimetric water content; and electrical conductivity of saturated soil paste. Coefficients of correlation between ECaand gravimetric soil water content (0.685 for ECa-V and 0.649 for ECa-H) were higher than those between ECaand clay content (ranging from 0.197 to 0.495, when different ECarecording dates were taken into account). Ordinary and universal kriging have been used to assess the patterns of spatial variability of the ECadata sets recorded at successive dates and the analyzed soil properties. Ordinary and universal cokriging methods have improved the estimation of gravimetric soil water content using the data of ECaas secondary variable with respect to the use of ordinary kriging.

Dependence of Soil Properties under Alpine Lichen Heath Community on the Soil Water Content and the Presence of Vaccinium vitis-idaea

2020 ◽  
Vol 53 (7) ◽  
pp. 941-949
Author(s):  
M. I. Makarov ◽  
R. V. Sabirova ◽  
M. S. Kadulin ◽  
T. I. Malysheva ◽  
A. I. Zhuravleva ◽  
...  
Keyword(s):  
Soil Properties ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Heath Community

scholarly journals Separation of soil and canopy reflectance signatures of Mid German agricultural soils

2011 ◽  
Vol 51 (No, 7) ◽  
pp. 296-303 ◽  
Author(s):  
T. Behrens ◽  
K. Gregor ◽  
W. Diepenbrock
Keyword(s):  
Remote Sensing ◽  
Soil Properties ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Vegetation Index ◽  
Near Infrared ◽  
Field Experiments ◽  
Agricultural Soils ◽  
Soil Reflectance

Remote sensing can provide visual indications of crop growth during production season. In past, spectral optical estimations were well performed in the ability to be correlated with crop and soil properties but were not consistent within the whole production season. To better quantify vegetation properties gathered via remote sensing, models of soil reflectance under changing moisture conditions are needed. Signatures of reflected radiation were acquired for several Mid German agricultural soils in laboratory and field experiments. Results were evaluated at near-infrared spectral region at the wavelength of 850 nm. The selected soils represented different soil colors and brightness values reflecting a broad range of soil properties. At the wavelength of 850 nm soil reflectance ranged between 10% (black peat) and 74% (white quartz sand). The reflectance of topsoils varied from 21% to 32%. An interrelation was found between soil brightness rating values and spectral optical reflectance values in form of a linear regression. Increases of soil water content from 0% to 25% decreased signatures of soil reflectance at 850 nm of two different soil types about 40%. The interrelation of soil reflectance and soil moisture revealed a non-linear exponential function. Using knowledge of the individual signature of soil reflectance as well as the soil water content at the measurement, soil reflectance could be predicted. As a result, a clear separation is established between soil reflectance and reflectance of the vegetation cover if the vegetation index is known.

Hydrologic soil properties and application of a soil moisture model in a balsam fir forest

1988 ◽  
Vol 18 (4) ◽  
pp. 427-434 ◽  
Author(s):  
Richard Barry ◽  
André P. Plamondon ◽  
Jean Stein
Keyword(s):  
Soil Moisture ◽  
Soil Properties ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Crop Coefficient ◽  
Balsam Fir ◽  
Physical Parameters ◽  
Volumetric Soil Water Content ◽  
Soil Moisture Model

An analysis of hydrologic soil properties and the prediction of volumetric soil water content during four summers have been done for a site located in the balsam fir (Abiesbalsamea (L.) Mill.) forest of the Lac Laflamme watershed. The hydrologic properties were used to identify three different soil layers, THIRSTY, a soil moisture model using the Penman evapotranspiration formula, was applied to predict daily volumetric water content of these layers. Predictions of soil moisture with the calibrated model were close to the observed data for the median layer (20–60 cm from the soil surface) and less accurate for the surface layer (0–20 cm) where important transpiration activities take place. The model appeared unreliable for predicting soil water content of the bottom layer (60–100 cm) which was often saturated by groundwater. The calibration of the model required modifications of the observed values of the available water content at field capacity and the relative root density factor and was adjusted with the crop coefficient of the Penman evapotranspiration formula. These modifications of observed physical parameters raise the question of the feasibility of extrapolating the model to other sites without extensive calibration. The high sensitivity to variations of the crop coefficient applied to the evapotranspiration equation indicated that a more physically based transpiration model, supported by field-oriented process studies, would be required to improve the model's performance.

Vegetation impacts soil water content patterns by shaping canopy water fluxes and soil properties

2017 ◽  
Vol 31 (22) ◽  
pp. 3783-3795 ◽  
Author(s):  
Johanna Clara Metzger ◽  
Thomas Wutzler ◽  
Nicolas Dalla Valle ◽  
Janett Filipzik ◽  
Christoph Grauer ◽  
...  
Keyword(s):  
Soil Properties ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Water Fluxes ◽  
Canopy Water

scholarly journals Field scale variability of solute transport parameters and related soil properties

1997 ◽  
Vol 1 (4) ◽  
pp. 801-811 ◽  
Author(s):  
B. Lennartz ◽  
S. K. Kamra ◽  
S. Meyer-Windel
Keyword(s):  
Soil Properties ◽  
Solute Transport ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Preferential Flow ◽  
Type I ◽  
Transport Parameters ◽  
Undisturbed Soil ◽  
Soil Hydraulic

Abstract. The spatial variability of transport parameters has to be taken into account for a reliable assessment of solute behaviour in natural field soils. Two field sites were studied by collecting 24 and 36 small undisturbed soil columns at an uniform grid of 15 m spacing. Displacement experiments were conducted in these columns with bromide traced water under unsaturated steady state transport conditions. Measured breakthrough curves (BTCs) were evaluated with the simple convective-dispersive equation (CDE). The solute mobility index (MI) calculated as the ratio of measured to fitted pore water velocity and the dispersion coefficient (D) were used to classify bromide breakthrough behaviour. Experimental BTCs were classified into two groups: type I curves expressed classical solute behaviour while type II curves were characterised by the occurrence of a bromide concentration maximum before 0.35 pore volumes of effluent (MI<0.35) resulting from preferential flow conditions. Six columns from site A and 8 from site B were identified as preferential. Frequency distributions of the transport parameters (MI and D) of both sites were either extremely skewed or bimodal. Log-transformation did not lead to a normal distribution in any case. Contour maps of bromide mass flux at certain time steps indicated the clustering of preferential flow regions at both sites. Differences in the extent of preferential flow between sites seemed to be governed by soil structure. Linear cross correlations among transport parameters and independently measured soil properties revealed relations between solute mobility and volumetric soil water content at time of sampling, texture and organic carbon content. The volumetric field soil water content, a simple measure characterising the soil hydraulic behaviour at the sampling location, was found to be a highly sensitive parameter with respect to solute mobility and preferential flow situations. Almost no relation was found between solute transport parameters and independently determined soil properties when non-preferential and preferential samples were considered separately in regression analyses. Future work should concentrate to relate integrated parameters such as the infiltration rate or the soil hydraulic functions to solute mobility under different flow situations.

Effect of variability in soil properties plus model complexity on predicting topsoil water content and nitrous oxide emissions

Soil Research ◽  
2018 ◽  
Vol 56 (8) ◽  
pp. 810 ◽  
Author(s):  
Iris Vogeler ◽  
Rogerio Cichota
Keyword(s):  
Nitrous Oxide ◽  
Soil Properties ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Profile ◽  
Nitrous Oxide Emissions ◽  
Soil Types ◽  
N2o Emissions ◽  
Silt Loam

Despite the importance of soil physical properties on water infiltration and redistribution, little is known about the effect of variability in soil properties and its consequent effect on contaminant loss pathways. To investigate the effects of uncertainty and heterogeneity in measured soil physical parameters on the simulated movement of water and the prediction of nitrous oxide (N2O) emissions, we set up the Agricultural Production Systems sIMulator (APSIM) for different soil types in three different regions of New Zealand: the Te Kowhai silt loam and the Horotiu silt loam in the Waikato region, and the Templeton silt loam in the Canterbury region, and the Otokia silt loam and the Wingatui silt loam in the Otago region. For each of the soil types, various measured soil profile descriptions, as well as those from a national soils database (S-map) were used when available. In addition, three different soil water models in APSIM with different complexities (SWIM2, SWIM3, and SoilWat) were evaluated. Model outputs were compared with temporal soil water content measurements within the top 75mm at the various experimental sites. Results show that the profile description, as well as the soil water model used affected the prediction accuracy of soil water content. The smallest difference between soil profile descriptions was found for the Templeton soil series, where the model efficiency (NSE) was positive for all soil profile descriptions, and the RMSE ranged from 0.055 to 0.069m3/m3. The greatest difference was found for the Te Kowhai soil, where only one of the descriptions showed a positive NSE, and the other two profile descriptions overestimated measured topsoil water contents. Furthermore, it was shown that the soil profile description highly affects N2O emissions from urinary N deposited during animal grazing. However, the relative difference between the emissions was not always related to the accuracy of the measured soil water content, with soil organic carbon content also affecting emissions.

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